This invention relates generally to a device for cleaning the magnetic read/write head of a computer floppy disk drive.
Many computers utilize well known floppy disks as low-cost storage media. They are flexible sheaths that house a thin, flexible magnetic material. When properly placed in a computer disk drive and clamped in place, a central hub that extends through a central hub receiving opening in the shaft grips the magnetic disk to rotate the disk. A head in the drive mechanism moves along a window or head receiving aperture in the sheath and rides on the rotating disk. The computer moves the head radially in and out along the window, and the disk rotates. Therefore, the head can reach every usable portion of the disk. This of course is conventional.
As with any head that makes contact with a magnetic medium, whether it be audio or video tape or a computer floppy disk, there is friction between the head and the magnetic material. This action causes a slight removal of magnetic material or oxide from the magnetic medium, and the magnetic material builds up on the head. As the build up becomes too severe, read and write errors may occur. Moreover, as material builds up on the head, the head increases its coefficient of friction, and the wear process increases.
Therefore, it is important to remove any built up oxide or other magnetic material from the heads. One method--perhaps the simplest--required the user to wipe the heads with a cotton swab dipped in alcohol or other solvent. Although this is a standard method for cleaning audio tape recorder heads, the heads are much less accessible on a floppy disk drive, and this method is not practical.
Another method of cleaning a head involved the use of a dry, mildly abrasive material. For example, an audio cassette is wound with a relatively short length of a mildly abrasive type. This is run through the tape recorder a number of times so that the abrasive tape travels over the head and removes the oxide. Some audio tape manufacturers build in a short leader of abrasive material for cleaning the head each time the tape is played. Unfortunately, abrasive material is ultimately detrimental to the head. Although magnetic heads are made of very hard, wear resistant materials, use of a material sufficiently abrasive to remove oxides is incompatible with long head life. Even where the dry cleaner is not abrasive but uses a material that tends to dislodge the oxide and pull it off, the dry cleaning action is not completely effective in removing oxide. Consequently, the most difficult oxide to be removed is never removed, and the head continually stays dirty.
To utilize through the wet cleaning action of a solvent-dipped swab with the convenience of an automatic cleaner that is inserted into a position for cleaning the head, tape head cleaners have been developed. See e.g. Kara, U.S. Pat. No. 4,141,053 (1979). For an audio cassette tape recorder, for example, a solvent such as isoprophyl alcohol is applied to an absorbent roller. When the cassette is inserted into the tape recorder, the absorbent roller is in contact with the head, and the tape recorder drive mechanism causes the roller to rotate. The solvent dissolves the oxide on the head, and the rotating absorbent material removes the oxide. It has been found that the alternating wet and dry areas in more effective in oxide removal. Other systems have been developed for video tape recorders (See e.g. application Ser. No. 325,923 (1981) of Kara) and for computer floppy disk drives.
In Sugisakim U.S. Pat. No. 4,065,798 (1977), the standard outer sheath of a floppy disk is used, but a round flat piece of fabric is inserted in the sheath. Rotating the fabric, which will contact the head, removes oxide from the head. A solvent can be applied to the fabric to dissolve the built-up oxide and the oxide is removed from the head by the fabric rotating passed it. Masuyama, U.S. Pat. No. 4,106,067 (1978) describes the use of solvents.
There are a number of problems with this system. First, there may be an insufficient area for applying solvent to the fabric. As previously mentioned, it is desirable to have both a wet and dry area. The wet area applies the solvent to the oxide, and most of the oxide will be removed in the dry area. Existing floppy disk head cleaners utilize standard sheaths with narrow windows through which the head can contact the magnetic material. The window does not have to be wide on a floppy disk; the head does not move laterally.
In a typical floppy disk drive, the floppy disk can only be inserted properly into the disk drive in one orientation. Thus, the operator must be at least skilled enough to known how to insert the floppy disk properly. If the disk is not inserted properly, the system will not operate. Therefore, the operator gets instant feedback if he or she incorrectly inserts the floppy disks and attempts to use it. With a head cleaner, however, the computer will not tell the operator that the cleaner is incorrectly inserted.